5.Which is the first step in photosynthesis?. a. the production of ATP
b. the absorption of light
c. the production of NADPH
d. None of the above

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.

Color blindedness is a sex-linked trait. if we could see the pedigree chart for several more generations of the family illustrated here, we would expect a) more males to be color blind. eliminate b) more females to be color blind. c) no females to ever be color blind. d) an equal number of males and females that are color blind.

Which one of the following is true of trnas? a) trnas are double-stranded. b) each trna binds a particular amino acid. c) there are four types of trna. d) trnas carry special sequences known as codons. e) all of the above